As cell phones with cameras in which a camera is mounted have become popular in recent years, chances photographing various objects to be photographed by using the cell phone have increased. For example, there is a case that an object such as a friend or landscape which is apart from a lens of a camera to some extent is photographed (normal photographing) and, alternatively, there is a case that an object such as a timetable for bus or petals of a flower at a position near the lens of the camera is photographed (close-up photographing).
In the close-up photographing (macro-photographing), a lens position of a camera is required to locate at a position nearer on an object side than a lens position at the time of normal photographing. Therefore, this type of photographing lens system is provided with a drive mechanism for driving a lens to move in the optical axis direction. The drive mechanism is driven by changing a switch to move a lens in the optical axis direction (see, for example, Japanese Patent Laid-Open No. 2006-227103).
An imaging device which is disclosed in the above-mentioned Patent Reference includes a lens-barrel on which an imaging optical system is disposed, a movable part which is provided with a movable lens and which is movable with respect to the lens-barrel in an optical axis direction, a linear actuator for moving the movable part in the optical axis direction, a holding part which holds the movable part, and a plurality of spring parts which are capable of being elastically deformed. Further, the movable part includes a lens holder, a drive coil and a coil holder. In the structure as described above, the movable part can be moved from an infinity side to a macro-end side by means of driving the linear actuator through energization to the drive coil. As a result, the movable part can be stopped at a desired position.
End parts of the drive coil are wound around coil connecting protruded parts which are formed on a coil holder. Further, the coil connecting protruded parts are formed so as to protrude upward and downward on an upper and a lower end parts of the coil holder. In addition, after the drive coil has been wound around the coil connecting protruded part, in order to enhance a conducting function or, in order to securely connect the drive coil to the coil connecting protruded part, soldering is commonly performed to the drive coil.
However, when the drive coil and the coil connecting protruded part are electrically connected by soldering, the soldered portion has heaped up and thus a design space is narrowed. In other words, when the soldered portion has heaped up, the design space is narrowed because a distance between the soldered portion and its opposite part is required to secure. In addition, in order to secure a sufficient distance between the soldered portion and its opposite part, a thickness and a size of the device is required to increase, which does not meet recent demands for miniaturization of the device.
On the other hand, a camera which is mounted on a cell phone with a camera or a digital camera includes a lens drive device for moving a lens in an optical axis direction. The lens drive device includes a support body, a movable body provided with a lens, and a spring member which movably supports the movable body along an optical axis of the lens. The spring member includes a support body side fixing part which is fixed to the support body, a movable body side fixing part which is fixed to the movable body, and a plurality of arm parts which are formed in a plate spring shape to connect the movable body side fixing part with the support body side fixing part (see, Japanese Patent Laid-Open No. 2006-201525).
The spring member is commonly manufactured by means of that a thin plate is cut off by wet etching processing which utilizes a photo lithography technique.
In the lens drive device described above, the movable body is driven in an optical axis direction by a magnetic drive mechanism which is structured between the support body and the movable body, and its movement is restricted by the spring member to determine a stop position of the movable body. Therefore, a high degree of accuracy is required for a spring constant of the arm part of the spring member. However, a spring member having a spring constant with a high degree of accuracy is not obtained by a conventional manufacturing method. This problem is not limited to the spring member used in the lens drive device but may occur in all spring members which are used in apparatuses in which a position of a movable body is restricted by a spring member. Especially in the lens drive device, the spring member having a thinner thickness and the arm part having a thinner width are strictly demanded as its size and height are reduced. Therefore, also from this standpoint, control of its spring constant becomes difficult.